window balances
Thanks for reaching out to us! There is a chance replacing the shoe or the pivot bar (or both) could correct the issue, but I cannot make any guarantees. Take a look at the 15-218 and 15-220 on the website, and see what you think. These are both compatible with the 26-424 Pivot Bar.
If that does not solve the issue, then you may need to replace the balances.
The window balance is a jamb liner spring balance. Unfortunately, we do not have a suitable replacement for it. You'll need to reach out to the manufacturer directly to inquire about what your replacement options might be.
Our sincerest apologies that we could not be of more help with this part of the repair!